Not all days at the Nürburgring are rainbows and unicorns, as evidenced by this 2012 Mercedes SLK prototype breaking down and spewing smoke in the tester's first run. Yeah, that's a bad day.

The car puttered to a stop after only one lap on the 'Ring and pulled off at the Brünnchen section. The two passengers jumped out of the car fire extinguisher in hand and quickly inspected the situation. There was no dramatic and schadenfreude-inducing drama like the time an Audi R8 V10 went up in flames, but this is good enough. [WorldCarFans]